Explanation:
The universe is filled
with
galaxies.
But to see them astronomers must
look out beyond the stars of
our galaxy,
the Milky Way.
For example,
consider this
colorful telescopic view of
spiral galaxy NGC 6384, about 80 million light-years
away in the direction of the constellation Ophiuchus.
At that distance, NGC 6384 spans an estimated 150,000 light-years.
The sharp image shows details in the distant galaxy's blue spiral
arms and yellowish core.
Still, the individual stars seen in the picture
are all in the close foreground, well
within our own
galaxy.
The brighter Milky Way stars show noticeable crosses, or
diffraction spikes,
caused by the telescope itself.
This particular field of view is about 1/4 degree wide and
is relatively rich in foreground stars because it
looks out
near the crowded center of the Milky Way.